US2011000A

US2011000A - Universal type machine tool unit with differential feed

Info

Publication number: US2011000A
Application number: US685760A
Authority: US
Inventors: Kingsbury Edward Joslin
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-08-18
Filing date: 1933-08-18
Publication date: 1935-08-13
Anticipated expiration: 1952-08-13

Description

Aug. 13, 1935. E. J. KiNGsBURY 2,011,000

UNIVERSAL TYPE MACHINE TQoI. UNIT WITH DIFFERENTIAL FEED Filed Aug. 18, 1933 5 Sheets-Sheet 1 gmc/m.'

Aug. 13, 1935. E, J KINGsBURY UNIVERSAL TYPE MACHINE TOL UNIT WITH DIFFERENTIAL FEED Filed Aug. 18, 1933 5 Sheets-Sheet 2 .o mw Nww u E E y .l All .u N? uu //y/. wb m .w q m. w... ..3 .ww E. @M1 QM J @o A@ NN\ Hs l P I l Il h vm/ H I a b P l www w/ mw df f w W1 E m. \x @I sw. N uw I y l v1 u l ma. 1| n. n W l R. m. kf 9.... 3

Aug. 13, 1935. E. .LKINGSBURY UNIVERSAL TYPE MACHINE TOOL UNIT WITH DIFFERENTIAL FEED Filed Aug. 18, 1933 5 Sheets-Sheet 3 Aug. v13, 1935. I E. J. KINGsBuRY 2,011,000

UNIVERSAL TYPE MACHINE TOOL UNIT WITH DIFFERENTIAL FEED Filed Aug. 18, 1953 5 Sheets-Sheenl 4 l 57g- 6' 24 20 712s' EdwafrdJ-nywy Aug. 13, 1935. y E. J. KINGSBURY 2,011,000

` UNIVERSAL TYPE MACHINE TOOL UNIT WITH DIFFERENTIAL FEED Filed Aug. 18, 1953 5 Sheets-Sheet 5 Patented 4Aug. v13, v1935 UNITED STATES PATENT oFFicE UNIVERSAL TYPE 4MAoimui Tool. .WITH DIFFERENTIAL FEED Edward Josiiiixiiigspury, Keene, n.11. i y f v Application August 18.1933, serial 10.685.760 iz'oiaima (cria-12s) This invention relates to improvementsinzmaf chine tool units including means for driving; and feeding a tool with respect to the work, f

One of the features of the present invention is the provision of such a tool unit with-two tool devices, of such nature that one tool may be constantly rotated while the other tool is reversed with reversal of feeding movement of whereby a tap or like tool may beused.

Another feature of the present invention is the provision of a .machine tool unit havinga single driving motor for delivering its power to the tool, to the feeding means for the tool, and to acontrol for the feeding means, the driving system to the feed' controlling 'means including a slip clutch,

the topi,

'together with stops for limiting the movement-of a feed control structure 'so that predetermined conditions of feed may be accomplished..

.A further feature of the presenti'nvention is 20': the provision of a fed control mechanism \in cluding a cntinuiailyrotated devicc wit h'movable stops for intermittently' limiting the movement of-such device, and meanson' two structures stops.

which move with relation 'tonne-another during feeding, said means operating for moving said f Still another feature of the-present invention the provision of a-feed control"in'cli'idi'ng cam devicesa'nd two pairs of 'clutches operated thereby, together with stops fo'r limiting and determin-l ing the intermittent movement ofi' the cam devices, and a drivigsystem including said clutches for selectively providing a plurality. oi'

speeds and directions of feed.'

A still further feature of the invention isl the, provision of a feed control mounted on a movable carriage and including a feed control de` vice which is intermittently moved by angular increments, together with feeding mechanisms selectively operated by said device, and'means on afxed frame for controlling the movement of said device.

Still another feature of the present invention is the provision of a feed control mechanism driven independently of a feed mechanism, with pairs of double clutches in said feed mechanism which are selectively operated by said feed control mechanism, one of said clutches being capable of engagement with a non-rotatable structure whereby to prevent rotation of a portion of the' feeding mechanism under predetermined conditions of feed control.

Still further features of the invention relate to specific forms of construction and will be apparent in the course of the following speclcation and claims.

An illustrative form of construction is set forth in the accompanying drawings, in which:

Figure 1 is a side elevation of the apparatus vided with a reamer and a tap.

Figures 1a and 1b are respectively transverse upright sections substantially on lines Ia-ia and-Ib-lb of Figure 1.

Figure 2 is a development view, on a larger scale, of the driving system, substantially on line 2 2 of Figure 3, but with the several shafts shown in a single plane to represent the driving connections between these shafts.-

Figure 3 is an upright sectional view, substantially on lines 3 3 of Figures 1 and 2.

Figures 4 and 5 are fragmentary similar views substantially on lines 4 4 and 5 5 of Figure 1.

' Figure 6 is a similar view substantially on lines lG BoiFiguresZandQ.

Figure 7 is a fragmentary elevation of parts shown in Figure 1, and indicating in dotted lines certain parts located inside the housing side plate.

Figure 8 isa fragmentary longitudinal upright sectional view substantially on line 8 8 of Figure 4.

Figure 9 is a development view substantially on the broken line 9 9 of Figure 3'.

Figure 10 is a fragmentary transverse sectional view substantially on line i9 |0 of Figure 9. Figure 11 is a longitudinal sectional view sub- Figure 12 is a horizontal sectional view substantially on lines l2 |2 of Figures 7 and 10.

The apparatus illustrated on the drawings includes a fixed frame and a travelling carriage stantially on line I I Il of Figure 10.

movable reciprocably along the frame. This able fixed dogs on the frame for obtaining the desired reciprocating feeding movement of the carriage with respect to the frame. The feed control structure-includes electrical devices `whereby -the structure according to the present invention is adapted for incorporation in a unity-assembled machine tool including one or more of these units along with a turret control unit: such arrangements have been shown in my prior applications Serial No. 405,172, iled November 6, 1929; Serial No. 607,839; filed April 27, 1932; Serial No. 633,888; filed Sept. 19, 1932; and in conjunction with the indexing uni-ts shown and described in my application Serial No. 683,541; filed August 3, 1933 and Serial No. 676,574; filed June 19, 1933.

In Figure l of the drawings, the xed frame 2li has a carriage 2| reciprocably guided thereon by suitable ways as indicated in Figure 2. This carrage supports a main driving motor M, a housing H for a speed reduction gear train and the gears iwan a tool unit in posicion thereon which is proof the speed and feed control mechanisms, and an interchangeable tool unit T. The portion of the housing H containing the speed and feed mechanisms, and -their controls, is -accessible through the

sidel closing plates

22, 23 and the top closing plate 24. p

As shown in Figures 1, la. and 2, the shaft 25 of .the driving motor M is connected through a flexible coupling with a short shaft 26 having a small gear 21 thereon in mesh with a large gear 28 on a counter shaft 29 having a small gear 38 in mesh with a large gear 3| on the main driving and speed shaft 32. Shafts 25-26 and 32 are offset with respect to one another as shown in Figure la, although apparentlyV appearing in the same plane in Figure 2. This speed reduction system produces the desired speed of shaft 32 before operation of motor M. It will be understood that this motor is in operation constantly'while the apparatus is connected for drive, so th'at the main driving shaft 32 is turning constantly in a given direction.

Keyed to the main speed and feed shaft 32 is a driving member 33 having cavities in one axially directed face, for cooperationwith the driving pins 34 which are axiall`y movable in one portion of the body of a gear member having a first set of gear teeth 35 oi.' large diameter thereon and a secondset ofgear teeth 36 of smaller diameter. 4In Figure 2, one of these pins is shown in section, with its associated parts: while the positions for four such pins are shown in Figure '3l The pin 34 is normally urged toward the left in Figure`2 by an adjustable spring 31 and is guided by a rod 38 carried by an adjustable screw 39 which is threadedly engaged in the`body structure which has the set of gearteeth 36. A reaction collar 49 is forced toward the left by screw 39 for adjusting the compression' of spring 31, whereby to de-n termine the relative 'torque effect between members 33 and 34 at which the beveled ends of pins .34 will be forced axially toward the right (Fig. 2)

for disconnecting thel drive a-t overload. The main speed and feed shaft 32 .is free to turn within the gear assembly 35, 36 when the drive is thus interrupted.

The setV 35 of gear teeth of larger diameter are in mesh with a gear 4| having a grooved member f engaged by plates 42 for preventing relative axial movement of gear 4| along the second and reversible speed shaft 43 upon which it is mounted, but permitting free relative'rotation of the gear 4i with respect to -the second speed shaft 43. The gear 4| also has clutch teeth 44 at one face thereof for engagement with clutch teeth 45 of a clutch member 46 having a. second set of clutch teeth 41 for engagement with clutch teeth 48 of a gear 49 diameters inthe gear teeth 35-4I or 36--49.

Clutch member 46 is splined tothe second speed shaft 43 and drives the latter.

At one end of the second speed shaft 43 isk keyed a gear 5| which is in mesh with a larger gear 52 on a feed control-shaft 53 which has mounted thereon for free rotation a clutch member 54 having clutch teeth 55 at one end for engagement with clutch teeth. 56 on a. sleeve 51 keyed to feed control shaft 53. Clutch member 54 also has a second set of clutch teeth 58 thereon for engagement with clutch teeth 59 held fixedly to the housing H. The clutch member 54 also has a gear 68 formed integrally therewith andin mesh with gear teeth 6| on a nut 62 which is engaged with the threads 63 of the rotating portion 69 for receiving anti-friction bearings 10 which may adjust themselves within a sleeve 1| likewise supported by the fixed frame 20. The squared end 12 of feed spindle 64 may be turned manually during preliminary adjustments of the apparatus. The nut. 62 is supported by antifriction bearings 13 carried by a downward extension 14 of the carriage which is located within an oil sump space 15 (Fig. 3) provided in the fixed frame. Nuts 16 are engaged with the nut 62 and act in cooperation with the anti-friction bearings for preventing relative axial movement of the'nut with respect to the extension 14.

Keyed to the second speed shaft 43 is a gear 80 which is in mesh with a gear 8| carried loosely for rotation about the axiseof the feed shaft 53 and operating as an idler to transmit the drive` of gear 8U to a gear 82 which surrounds the spindle 64 and is provided with keys 83 (Figs. 2 and 6) engaged in keyways 84 of spindle 64. Gear 82 is supported'by anti-friction bearings 85 for free rotation in the downward extension 14 and a nut 86 is provided to prevent relative axial movement of gear 82 with respect to extension 14. Thus, when the second speed shaft 43 is driven in one `or the other direction, the feed spindle 64 is rotated in the same direction and at a speed controlled by'the ratio of

gears

80 and 82.

-

Gears

81 and 88 are keyed to the forward ends of the first and second speed shafts 32 and 43 (to the right in Figs. 1 and 2) and are employed for Since the first speed shaft 32 turns constantly in one direction, the tool mounted thereon turna always in one direction regardless of its feeding to and from the work. Similarly, a countershaft 93 is provided within the tool unit T and has a gear 94 in mesh with gear 88 and a gear 95 in mesh with a gear 96 on a second tool shaft 91 which is provided externally of the tool unit'T with a second holder 98 which may support a tap 93. Since the second speed shaft 43. is reversed periodically during the forward and reverse feeding movements of the carriage with respect to the work, and always turns at a speed which'is in unison with the feeding movement of the carriage, the tap is properly engaged with the work bothduring rapid and slow movements, in either direction. Taps of any thread pitch may be employed by a proper selection of gears 5 i-52, 88-94 and 95--96.

The idler gear 50 is supported for rotation about a'xed shaft |00 (Figs. 3 and 6) and is in mesh not only with

gears

An anti-friction bearing sleeve |06' surrounds the shaft |05 and receives a worm |01 for free relative rotation, this worm being provided with a second friction clutch member |08 engageable with clutch member |04, and being normally forced toward engagement with this clutch member I 04 by a spring |09 which has reaction against a thrust bearing 0. Worm |01 is engaged with the teeth of a worm wheel which is constructed at the face adjacent the closing plate 22 with an inserted and fixedly mounted ring ||2 having four pins ||3, ||4, ||5, ||6 thereon; the pins ||3, I|5 being at greater radial distances from the axis than'pins |4, I6 and pin I|4 being higher than pin I 6. The worm wheel I|I is illustrated as constructed integrally with a shaft portion ||1 which is mounted in a bearing on the closing plate 22 and extends to the exterior thereof, so that an end plate I I0 and screw ||9 are operative to hold the worm wheel against axial movement. The face of the worm wheel remote from the side plate 22 is provided with an outer cam track and an inner cam track`A |2| (Figs. 8 and 11) in which respectively engage the control fingers |22 and |23. Finger I 22 is carried by a block |24 having a downwardly and inwardly extending fork |25 for engaging in the groove of 'clutch 54.- Similarly, control pin |23 is supported by a body |26 having a downwardly and inwardly projecting fork |21 for engagement in the groove of clutch 40. The control bodies |24 and |20 are slidable on guide rods |28 and |29 which are mounted in the walls of housing H. Thus, as' the worm wheel rotates, the clutch pins |22, |23

are shifted in predetermined relationships to one another and thus the control of lthe feeding system is effected.

Normally, the motion of the worm wheel is arrested at intervals, and then permitted to proceed. During the quiescent intervals of .worm wheel the continued drive from gear |03 causes the worm |01 to back up, so to speak, on

K the worm wheel and break the frictional drive between friction members |04 and |08. The Worm wheel I turns continually in one direction only as indicated by the arrows in Figures 7, 8, 9 and l1.

The intermittent rotation of worm wheel III may be controlled by dogs fixed on the frame.

' As shown in Figures 1 and?,` the frame 20 is provided with a structure having a T slotV for receiving' the binding screws |36 of three dogs, |31, |38 and |39. Dog |31 is provided with a downwardly directed inclined surface for moving the pin |40 (Figs. 4 and 7) of a vertical plunger 4| downwardly when this plunger is presented to the dog |31. Correspondingly, the dog |38 has an upwardly directed and doubly inclined surface for pushing the pin |40 upwardly. The dog |39 has a downwardly directed surface similar to that of dog |31 and operating in the sameway. A guide |42 on side plate 22 supports the plunger |4| in its vertical movementsas determined by the dcgs |31, |38 and |39. A pin |43 projects through the guide |42 and is carried by an arm |44 mounted on a rock shaft |45 extending through the side plate 22 (Figs. 7 and 12) and provided inside the housing H with a blocking arm |46 having a roller |41 which may engage selectively with the pins II3, and ||5.

AA second rock shaft |48 (Figs. 5 and 7) is mounted in the side plate 22 and is provided externally thereof with an upwardly extending arm |49. Inside the housing H, the second rock shaft |48 is provided with a blocking finger |50 having an onset end |5| which may engage only with the high portion of inner pin |I4 (Fig. 5) and is normally held in position for such engagement by a pressure spring I 50a and plunger |5|a, its position being determined by a stop pin |52.

The securing plate ||8 for the shaft ||1 of worm wheel is preferably formed as a cam, so that at one position of worm wheel ||I the operating roller |10 of a circuit closing switch I1| is actuated. This closing occurs when the carriage has reached the limit of its withdrawn position, i. e., the position as indicated in Figure 1: and the switch is connected in a control circuit which accomplishes the energization of the turret unit for indexing of a new piece of work to this apparatus, in the manner described in lmy aforesaid y co-pending applications.

Similarly, when the turret unit has completed the indexing of a new piece of work, the turret applications, whereby to energize the solenoid |62 and thus actuate the plunger |6| to start the apparatus into movement for a new cycle of operation.

The operation of this structure is as follows:

Theapparatus has completed a cycle and is ready for a new actuation when it is in the position of Figure 1, with the caniage fully withdrawn with respect to the frame, i. e., in its lefthand position. The motor is rotating. and tool 92 is turning at the speed predetermined by the gear trains. The tap 99 is ,ata standstill. Vertical plunger |4| has been raised by the reverse limit dog |31, and roller |41 on arm |46 is ready to engage an outer pin ||3 after the worm wheel I|| has begun to move. Finger |50- HI is engaged with an inner pin ||4 (Figs. '7 and 8) and holds worm Wheel IIIstationary. Cam track |20 is holding pin |22 and fork |25 in an intermediate position so that clutch 46 is disengaged from teeth 44 and 48. The second speed shaft 43 is thus at a standstill. Cam track |2| is holding pin |23 and fork |21, and therewith the clutch 54 in the lefthand position as shown in Figure 2. Neither the nut 62 nor gear 02 is rotating.

To start the cycle, the knob |63 is operated manually, or the solenoid |62 is energized from a remote point. The lever arm |49 is thus moved in a clockwisedirection in Figures l and 7, from the full line to the dotted line position in Figure 7 whereby finger |50, I.'a| releases the pin ||4. The drive which has been occurring from motor M to the first speed shaft 32 and therewith from gear 36 through idler 50, pinion |0I, gear |02, gear |03 to clutch member |04 is now permitted to operate as the spring |06 forces worm |01 and its friction member |08 into engagement with friction member |04. The worm wheel is thus given a partial rotation until pin ||3 encounters roller |41 and is stopped thereby. The cam track |2| has then moved the pin |23 and shifted clutch 4G to the left (Fig. 2). Clutch teeth are engaged with clutch teeth 44. Cam track |20 has held pin 22, so that the clutch teeth 58 are still engaged with the clutch teeth 50 on unit closes a circuit in a manner described in said l .the blocking' action of latch roller |41 while engaged with pin I i3.

When thepin |40, in its travel with the carriage, encounters. the dog |38`flxed on the frame, a

the pin is raised and therewith the plunger |4| so that, the roller |41 is raised and releases the pin II3. The worm wheel can now turn. During this turning of the worm wheel, the cam track |20 does not move the corresponding pin |22, so that clutch 46 remains in its lefthand position, and clutch teeth 44--45 .are engaged.' The movement of the worm wheel, however, operates through cam track |2| and the corresponding pin |23 to cause a movement of the lower clutch 54 toward the right in Figure 2 releasing the 'engagement of clutch teeth 58-59 and establishing an engagement of clutch teeth -56.

The former drive from the main speed and feed shaft 32 to the nut 62 continues. However, a second drive is now established from the rotating second speed shaft 43, through gear 5|-52 to feed control shaft 53 and its sleeve 51, by clutch teeth LSG-55, clutch 54, gear 60, to the nut 62 so that this nut turns in the same direction as the spindle and thus produces a lesser relative movement per revolution of the spindle than occurred during the rapid forward feeding. For example, if the nut 62 turns at :aI-10% lesser rate of angular speed than spindle 64, the fine forward feeding of the carriage with respect to the frame is accomplished at one-tenth of the rate of the rapid forward feeding. This relationship of rapid and fine forward feeding can be reguflated by proper selection of the relative pitch dithe path of pin m. During the turning or the Worm wheel III which has led to this change ofA the clutches, and therewith the accomplishment oi' the fine forward feeding, the worm wheel has ultimately presented its pin ||4 to the latch roller 41 so that the worm wheel is again brought to a standstill.

This fine forward feeding continues so long as the worm wheel I II is held against movement by the blocking action of the roller |41 engaged with pin H.

When the pin |40. in its travel with the carriage, encounters the dog |39 fixed on the frame, it is moved downwardly again, and roller |41 releases the pin |I4 so that the Worm wheel can turn again. The plunger I4! is held in the .lowered position with roller |41 in the path of pin H5. v

.The movement of the worm wheel now causes the cam track |20 to move the corresponding pin |22 for shifting the upper clutch 46 t0- ward the right (Fig. 2) so that the clutch teeth 44 and 45 are disengaged, and the

clutch teeth

41 and 48 are engaged. Furthermore, the cam track |2| moves its associated pin |23 so that the lower clutch 50 is shifted back to the left again, thus releasi g the engagement. of clutch teeth 55--56, and r -establishing the engagement of clutch teeth 58-55. As in the rapid forward feeding, the nut 62 is now held against relative rotation, for eecting a rapid reverse feeding. The drive for this purpose is obtained from the first speed shaft 32 by gears 36--50-49, clutch teeth 48-41, second speed shaft 43, gears 80--8i-82, and the spindle 64 is turned in the opposite direction than before, by reason of the inclusion of the idler 50 in this gear train.

The turning of the worm wheel l I is ultimately blocked by the engagement of roller |41 with pin I5. This, however, terminates when the pin |40 in its reversed' movement with the carriage again encounters the fixed dog |38 so that the plunger |4 and latch roller |41 are raised again. The worm wheel is then permitted a further rotational movement until pin H6 encounters the latch roller |41. During this further movement, the cam tracks |20 and |2| are circular and no movements of the clutches occur.

Ultimately, the pin |40 encounters the reverse limitdog |31 on the frame and is pulled downward thereby, so that the plunger I4| and latch roller |41 move downward and release pin H6.

The cam track |20 now operates on pin |22 to cause a movement of clutch 46 to a central or neutral position (shown in Fig. 2), where a driving of the second feed shaft 43 is prevented. The carntrack |2| is circular for this portion of the movement of worm wheel I, and there is no movement of the lower clutch 54. The movement of the worm wheel I I I is now interrupted (in the position of Figs. 'I and 8) by the engagement of finger |50, |5| with the high portion of pin I I4.'

The apparatus has thus made a complete cycle of movement, and has returned to its initial position. y

While the apparatus has been described in an illustrative embodiment, it is apparent that the invention is not limited specifically thereto, but

that it may be varied in many ways within the scope of the appended claims.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is:-

1. In an apparatus of the class described, a frame, a carriagemovable back and forth relative to the frame, a main shaft, a tool holder connected to said main shaft for drive therewith, forward and reversing members joined together and rotatable about the axis of said main shaft independently of the rotation thereof, a slip clutch for connecting said members to said main shaft for drive therefrom, a reversible shaft and means for connecting the same to said members and including shiftable clutch elements, and a tool holder connected to said reversible shaft for drive therewith.

2. In an apparatus of the class described, a frame, a carriage movable back and forth relative to said frame, a motor, a reversible shaft and feeding elements driven thereby for moving said carriage, means for selectively rotating said reversing shaft from said motor and including shiftable clutch elements, a cam for selectively shifting said clutch elements, means for driving lsaid cam from said motor, means for preventing the movement of said cam, and interengaging means on the carriage and frame for releasing said prevent- `ing means when the carriage attains predetermined positions relative to said frame.

3. An apparatus as in claim 2, including a second set of clutch elements also shifted by said cam and operative in one position for connecting said reversible shaft to said feeding elements and in another position for preventing movement of at least one element of the feeding mechanism.

4. An apparatus as in claim 2, including a second set of clutch elements also shifted by said cam and selectively operative for controlling the drive from said reversible shaft for moving said carriage, said cam being located on a wheel driven by said motor, and in vwhich said preventing means operates to limit the movement of said wheel after predetermined angular increments, and said interengaging means releases said preventing means for producing successively in cycle a rapid forward feed, a slow forward feeding and a rapid reverse feeding.

5. In an apparatus of the class` described, a frame, a carriage movable back and forth relative to said frame, a motor, a main shaft driven by said motor, a reversible lshaft, forward and reverse driving elements for connecting said main and reversible shafts and includingV shiftable clutch elements, means for feeding sayi carriage relative to the frame connected for drive by said reversible shaft and including shiftable clutch elements, a cam having two cam tracks, clutch shifting devices engaged with the clutch elements and in said tracks for selectively shifting the clutch elements, stop members on said l cam, means for driving said cam from the motor including a. slip connection, and cooperative means on the carriage and frame for releasing and engaging said stop members at predetermined positions of the carriage relative to said frame.

6. In an apparatus of the class described, a frame, a carriage movable back and forth relative to said frame, a motor, feeding means driven from said motor for feeding the carriage"rel'at ive to the frame and including shiftable clutch ele- 'ments, a cam wheel and means for driving the same from said motor, nieans for preventing movement of said cam wheel and releasing the drive thereof, means for releasing said preventing means at predetermined positions of the carriage relative to the frame, further stop means for detaining said cam wheel at a predetermined angular position-for determining the beginning and end of a cycle of carriage movements, and remotely controllable means for releasing said further stop means.

7. In an apparatus of the class described, a frame, a rotatable spindle journalled on said frame and having threads and a keyway, a carriage movable back and forth relative to said frame, a nut member on said carriage engaged l with the spindle thread, a member journalled on said carriage engaged with the keyway for rotating said spindle, and means selectively operable to rotate said nut and carriage member in the same or opposite directions and for holding one or both of said members at a standstill.

8. An apparatus as in claim '7, in which said selectively operable means includes a reversible shaft, a motor and first selectingclutch devices a carriage movable back and forth relative to said frame, a source of power, means including clutches driven by said source of power for producing feeding movements of the carriage relative to said frame, a cam wheel rotated from said source, stop members on said cam Wheel, shiftable means engageable with said stop members for limiting the rotation of the cam, selectively positionable dogs on said frame, means on said carriage cooperative with the dogs for shifting said engageable means, and devices actuated by the cam wheel during rotative movement thereof for selectively moving said clutches.

10. In an apparatus of the class described, a. frame, a carriage movable back and forth relative to said frame, a rotatable spindle journalled on said frame and having threads. and a keyway, a motor on said carriage, a main shaft on said carriage driven from said motor, a reversible shaft onsaid carriage, a feed control shaft on said carriage, forward and reverse driving devices for connecting said main shaft and reversible shaft and including first selective clutch elements, a nut member on said carriage engaged with the spindle threads, means including second selective clutch elements for connecting said feed control shaft to said nut member or to said carriage whereby to produce a rotation of said nut member with the reversible shaft or to hold the nut member at a standstill, a rotatable member carried by said carriage and engaged in' said keyway for rotating said spindle, means for driving said rotatable` member with the reversible shaft, and clutch actuating devices mounted on said carriage includ- .ing means for driving the same from said motor,

said shafts and spindle being mounted with their axes parallel to one another.

11. In an apparatus of the class described, a

frame, a carriage movable back and forth relative to said frame, a source of' power, a main shaft V for shifting said clutches whereby simultaneously to change the direction of feed of the carriage relative to the frame and to change the direction of rotation of said other tool holder.

12. In an apparatus of the class described, a frame, a spindle journalled on said frame for j rotation about its own axis, said spindle having threads and a keyway thereon, a cushion spring for urging said spindle in one direction and operative to absorb relative movement of the spindle with respect to the frame, a carriage, feeding devices on the carriage including a source of power and a reversible shaft driven therefrom, a rotatable nut member held against axial movement'relative to said carriage and engaged with the spindle threads, a rotatable member held against axial movement relative to said carriage and engaged in said keyway for rotating said spindle, and driving means for connecting said members and said reversible shaft.

EDWARD JOSLIN KINGSBURY.